Rotary printing machines are subject to tearing of the printed web. A paper web, which is passed through the printing machine and becomes torn can damage the machine since the torn web can wind itself about one of the cylinders or rollers of the printing machine. It has been proposed to cut the web, upon sensing a paper tear, by a paper cutter. The referenced U.S. Pat. No. 2,653,536 shows a system in which scissor-like cutters are located in the printing machine, arranged transversely to the running direction of the web. The cutter is operated when a "paper torn" condition is sensed, for example by a suitable and customary sensor. The paper is then severed.
The system is space-consuming and requires additional space within the printing machine. In normal operation, the cutter does not have any function; it is strictly a safety feature.